Sunan Ibn Majah, Chapter: The Book of Fasting

the wife of the Prophet (saw), that she came to visit the Messenger of Allah (saw) when he was in Itikaf during the last ten days of the month of Ramadan. She spoke with him for a while during the evening, then she stood up to go back. The Messenger of Allah (saw) got up to take her home. When she reached the door of the mosque that was by the home of Umm Salamah, the wife of the Prophet (saw), two men from among the Ansar passed by them. They greeted the Messenger of Allah (saw) with peace, then went away. The Messenger of Allah (saw) said: "Take it easy, she is Safiyyah bint Huyai." They said: "Glorious is Allah, O Messenger of Allah!" And they were very upset by that (i.e., that he thought they may have some doubts). The Messenger of Allah (saw) said: "The Satan flows through the son of Adam like blood, and I was afraid that he might cast some doubt into your hearts." Daif